Watlow CPC400 - Manual (Page 45)

CPC400 Series User’s Guide Chapter 2: Installation
Doc. 0600-2900-2000 Watlow Anafaze 31
Pulse Input Connections
The CPC400 can accept a pulse input up to 2000 Hz from a
device such as an encoder. The frequency of this input is
scaled with user-configured parameters; see Setting Up a
Process or Pulse Input on page 58. This scaled value is the
process variable for loop 5 on a CPC404, or loop 9 on a
CPC408.
The CPC400 can accommodate encoder signals up to 24V Î
(dc) using a voltage divider or can power encoders with the
5V
Î (dc) from the TB50 or TB18. The following figures
show how to connect encoders. A pull-up resistor in the
CPC400 allows open collector inputs to be used.
NOTE! If the signal on the pulse input exceeds 10kHz the
controller’s operation may be disrupted. Do not
connect the pulse input to a signal source that
may exceed 10kHz.
Figure 2.19 Encoder with 5V О О О О (dc) TTL Signal
Figure 2.20 Encoder Input with Voltage Divider
For encoders with signals greater than 5V Î (dc), use a volt-
age divider to drop the voltage to 5 volts at the input. Use
appropriate values for R
1
and R
2
depending on the encoder
excitation voltage. Do not exceed the specific current load
on the encoder.
Pulse Input
Com
Encoder
+5V Î (dc)
10 k
Ω
CPC400 and TB50 or TB18
Pulse Input
Com
Encoder
+5V Î (dc)
10 k Ω
R2
R1
CPC400 and TB50 or TB18